共查询到17条相似文献,搜索用时 125 毫秒
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为了提高电阻炉的温度控制效果,在AT89S52单片机的基础上设计出电阻炉控制系统。采用数字式温度传感器DS18B20作为系统的关键设备,该设备可有效强化温度采集的可靠性。利用PID控制算法与PWM脉宽调制技术控制电阻炉的温度,以此实现系统振荡与超调现象的消除,该算法具有编程简单、占用存储空间较少以及运算快等优势。通过对测试结果进行分析可知,该系统具有一定可行性。 相似文献
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为了精确控制恒温系统的温度,以STC89C52单片机为核心部件,采用单总线型数字式的温度传感器DS 18B20及行列式键盘,以容易控制的固态继电器SSR-40DA作加热控制的开关器件,设计了一种恒温系统.通过对系统软件和硬件的设计,发挥了单片机自身的优势,在不减少系统功能的前提下有效降低了硬件成本.实验证明:该温控系统能达到0.2℃的静态误差,0.45℃的控制精度,以及只有0.83%的超调量.系统具有功耗低、可靠性高、稳定性强、操作方便等优点. 相似文献
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介绍了一种新型智能全自动电锅炉控制系统,并给出了系统的工作原理、硬0件结构及软件流程。本系统采用ATMEL公司单片机系列中的AT89C52为CPU,选用MAXIM公司的微机监控电路和看门狗技术,应用铁电存储器FM1608S存储用户的参数设置,采用SSR作为开关器件,采用独特的新型单线智能数字温度传感器DS1820作为测温元件,测温精度可达0.5℃,这种数字传感器可以与单片机直接连接无需其它电路。文中采用二维模糊控制器构成单片机模糊检测与控制系统,并给出了模糊控制器系统的结构图、模糊控制规则基表和模糊控制表。实际使用证明该系统具有优良的测控效果,可使室内温度控制精度为±1℃。 相似文献
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随着科学技术的迅猛发展,各种总线技术相继以各自的优势在不同的领域得到应用。1-wire总线技术以其结构和设计简单,通讯链接方便,布线成本低等的特点,在金融、电信、商业以及军事等领域得到越来越广泛的应用。公共建筑的面积一般比较大,在测量温度时需要进行多点测量,为了避免复杂的布线,我们采用单总线方式,以DS18B20作为温度传感器,进行分布式温度采集。本文给出了该系统的硬件结构和软件流程,经现场调试、运行表明该方法的测量精度高,布线简单,非常适用于公共建筑的节能温控。 相似文献
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介绍了液化天然气的低温特性对工艺设计的影响,对主要工艺设备的设计原理和低温管道材质选用、柔性设计、绝热结构设计、管架管托设计、预冷等方面进行了探讨。 相似文献
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In this paper,the mechanical construction,thermal regulator design and temperature measurement system of alocal area were set up for large-scale linear measurement.Numerical analysis based on temperature correlatedcharacteristic is discussed to obtain optimal observation points for the measurements.The horizontal temperaturedistribution of the measured area is compared with the measurement of the variation of temperature at 15℃ and20~C over time,and characteristic of dynamic response is also discussed.In addition,the long-time stability ofmeasured temperature is analyzed by means of using the standard deviation.It characterizes the temperature dis-tribution performance of a large area and how it may impact the measurement of a large-scale object. 相似文献
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Abhishek Parikh Janna Martinek Greg Mungas Nick Kramer Robert Braun Guangdong Zhu 《国际能源研究杂志》2019,43(9):4051-4061
A linear Fresnel collector design with an operation temperature of 300°C or above typically requires a solar flux concentration ratio of at least 20 on the surfaces of the receiver assembly. For the commercial linear Fresnel collector design in this work, the receiver assembly includes a secondary reflector and an evacuated receiver tube. The high‐concentration solar flux may impose additional operating‐temperature requirements on the secondary reflector and receiver tube. Thus, a careful heat‐transfer analysis is necessary to understand the operating temperature of the receiver assembly component surfaces under design and off‐design conditions to guide appropriate material selections. In this work, a numerical heat‐transfer analysis is performed to calculate the temperature distribution of the surfaces of the secondary reflector and receiver glass envelope for a commercial collector design. Operating conditions examined in the heat‐transfer analysis include various wind speeds and solar concentration ratios. The results indicate a surface temperature higher than 100°C on the secondary reflector surface, which suggests that a more advanced secondary reflector material is needed. The established heat‐transfer model can be used for optimization of the other types of linear Fresnel collectors. 相似文献
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柴油机新型双卷流燃烧系统混合与燃烧机理研究 总被引:10,自引:2,他引:10
本提供了新型DSCS的结构和原理,其核心是在DS燃烧室内,燃油射流触脊,分裂并呈双卷流进行了混合与燃烧。在自制的燃油喷雾模型试验装置上,采用油-油喷射技术,对燃烧室模型内的燃油射流流动过程进行高速摄影,并对多种试验方案的拍照结果进行了分析。模型试验表明,DSCS中燃油射流流程可细分为4个阶段,采用了新机理,新理论进行了混合与燃烧。 相似文献
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Experimental investigation of moderately high temperature water source heat pump with non-azeotropic refrigerant mixtures 总被引:1,自引:0,他引:1
Experimental investigations were carried out on non-azeotropic refrigerant mixtures, named M1A (mass fraction of 20%R152a and 80%R245fa), M1B (mass fraction of 37% R152a and 63%R245fa) and M1C (mass fraction of 50%R152a and 50%R245fa), based on a water-to-water heat pump system in the condensing temperature range of 70–90 °C with a cycle temperature lift of 45 °C. Performance of R245fa was tested for comparison. Unfair factors in experimental comparative evaluation research with the same apparatus were identified and corrected. Experimental cycle performance of the mixtures were tested and compared with improved experimental assessment methodology. The results show that all of the mixtures deliver higher discharge temperature, higher heating capacity, higher COP and higher εh,c than R245fa. M1B presents the most excellent cycle performance and is recommended as working fluid for moderate/high temperature heat pump. 相似文献
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